Abstract: This article constructed an evaluation index system from four aspects: resource conservation, environmental friendliness, quality and efficiency, and rural development. The entropy method and Theil Index were used to objectively evaluate and analyze the level of agricultural green development and its regional differences in the western region from 2011 to 2021. On this basis, the Moran Index was used to test the spatial correlation of agricultural green development among different provinces. The results indicated that, (1) The level of agricultural green development in various provinces of the western region had been significantly improved, with rapid development in resource conservation and quality efficiency, followed by rural development, and environmental friendliness as its development weakness. (2) The overall difference in the level of agricultural green development in the western region from 2011 to 2021 showed a “W” shaped fluctuation trend. The differences in agricultural green development levels among provinces were constantly narrowing in the fluctuation, and the differences in the southwest region tended to be more stable than the differences in the northwest region’ s Theil Index. (3) There was a spatial agglomeration phenomenon in the green development level of agriculture in various provinces of the western region, and most provinces in the southwest region tended to be in a “high-high (H-H)” aggregation state, while provinces in the northwest region tended to be in a “low-low (L-L)” aggregation state. Furthermore, it was proposed to focus on environmental friendliness and rural development in the western region, address the shortcomings of green agricultural development, strengthen regional cooperation and exchanges, implement regional coordinated development strategies, and promote the formation of “high-high (H-H)” aggregation areas.